Girder



March 19, 1935.

w. B. KLEMPERER GIRDER Filed May 12, 1932 Patented Mar. 19, 1935 UNITEDSTATES PATENT orrics r v v Gianna I Wolfgang B. Klemperer,. Silver Lake,Ohio, as-

signor to Goodyear-Zeppelin Corporation,

Akron, Ohio, a corporation of Delaware Application May 12, 1932, SerialNo. 610,867

6 Claims.

The present invention relates to girders of the box type and moreparticularlyrelates to light-' a hollow beam or girder the individualstrips being lightened by removing portions of the metal to form a trussso that the total weight of the girder is substantially reduced Withoutdepreciable weakening thereof. The openings formed in the trusses areflanged so that the trusses and girder are better adapted to, resiststrain. Moreover, as disclosed in said patent, it has been the practicsin this art to flange the sides of the individual trusses and'to bendthem'in such forms that the sides or edges of the trusseswhen joinedtogether to form a girder provide individual tubular or semi-polygonalcorner portions which increase the strength of the girder. n

'It has been found that in box-type girders, corners which are tubularor polygonal in crosssection materially increase the strength of thegirdenas awhole and particularly adapt it, to resist compressionalstresses without buckling, such resistance very nearly approaching theyield point of the material from which the girder is fabricated. Withoutcorner constructions of this type it has been found thatcornpressionalstresses will cause buckling considerably "below theyield point of thematerial forming the truss and girder.

However, when the corners of the. individual trusses are initiallyformed so that the finished composite girder will have corners ofcircular or polygonal shape, considerable difliculty is experienced insecuring the individual trusses together inassembled relation and alsoin securing the finished girders into a framework. This is because thetrusses are ordinarily secured together at their sides or-edges usuallyby rivets, and this securing or riveting operation'is greatly interferedwith and sometimes renderedimpossibleby the shape of the corners oredges of the trusses. 7

It is an object of the present invention to avoid and overcome theaforementioned difiiculties of the prior art and-t0 provide a hollow orbox girder construction which is particularly adapted to resist stressessuch as produced in compression.

Another object of th invention is to provide a box girder made up ofindividual strips or trusses with filler or bridging plates positionedacross the corners thereof, whereby a very light,

strong girder is produced;

Another object of the invention is to provide a box girder made up ofindividual strips or trusses wherein the corners are formed circular orpolyg onal in cross-sectionbut in which the individual strips or trussescan be very readily riveted or secured together at their edges to form acomposite girder.

Another object of the invention is to provide a box girder withreinforced corners, which girders can readily be jointed at their endswith othe girders by riveting orthe like} Another object of theinvention is to provide an improved girder. v I l The foregoingand otherobjects of the inven tion are achieved by the girder construction de.-scribed below and, illustrated in the accompanying drawing, wherein V VFig. 1 is a fragmentary side elevation, of one form of girder embodyingthe principles. of. the invention; 7 v v I n v f Fig. 2 is aoross-scctional view ..taken on. line IIII of Fig. 1;

Fig. 3 is a side elevation illustrating the princi ples of the inventionapplied to another fornrof hollow box girder; v

Fig. 4 is a cross-sectional View taken on line IVIV of Fig. 3;

Fig. 5 isva side elevation, on a larger scale, 0 a corner or bridgingstripv employed in practicing the invention; 7 v

, Fig. 6 is a cross-sectional view taken on line VI-VI of Fig. 5, and

Fig. 7 is an elevation of how the girders comprising the presentinvention are joined together.

Referring more particularly to the drawing, the box girder illustratedin Figs. 1 and 2 comprisesfour individual truss members 11, 12, 13 and14. each of which is provided with aseries of large openings 16 andsmall openings 17. The edges of these openings. 16' and 17 are pressedor otherwise turned outward to provide flanges for purpose ofreinforcement is the usual-practice in this art. Furthermore, thelongitudinal edges of the individual trusses or strips 11, 12, 13 and 14are olfset or'otherwise formed with flanged portions 20, 21, 22 and 23respectively (see- Fig; 50E

2) which portions cooperate in overlapping relation to formsemi-polygonal corners of the composite girder. Rivets 25 or othersuitable means secure the individual trusses together at the corners aswill be apparent from the drawing. 55

f if.

a joint illustrating Addition filler or bridging plates 30 also connectthe adjacent truss plates, spanning the offset corner portions thereof,rivets 31 being employed to secure said plates 30 in position. Thesefiller or bridging plates 30 are provided with a plurality of openings32 for lightness of weight, said openings as well as the edges of thefiller plates 30 being appropriately flanged for strengthening the same,as indicated at 33 and 34 respectively. The construction of the filleror bridging plates 30 is illustrated particularly in Figs. 5 and 6 ofthe drawing wherein one of them has been independently shown on a largerscale.

Another embodiment of the invention is illus trated in Figs. 3 and 4,wherein the numerals 40, 41 and 42 indicate generally individual stripsor trusses which have been united along their edges to form a compositehollow girder, these individual strips or trusses being provided withflanged openings 43 and 44 similar to those of the firstdescribedembodiment. The edges of the individual trusses 40, 41 and 42 may besecured together in any one of a number of different ways, dependentupon the shape of the edges. In the triangular girder illustrated,corner channels 46 are provided to connect the adjacent truss plates,the individual trusses being secured to legs of the channel as by rivets47. Bridging or. filler plates 30, formed in the manner described above,are employed across the corners of this composite triangular girder, thesame being held in position by rivets 50.

As illustrated in Fig. '7, when the girders are joined together, as bygusset plates 54, the corner .pieces or bridging members 30 areterminated short of the ends of the girders as at 55 so that theoperation of, joining the'ends of individual girders together is greatlyfacilitated. The bridging members 30 are ordinarily terminated atsubstantially the beginning of the'gusset plates 54 as at 55 but it ha'sb'een found advisable in certain installationsto extend the membersslightly by the endsof the gusset plates as at 55 to permit the ends ofthe members to be riveted to the gusset plates.

From the foregoing it will be seen that by providing filler or bridgingplates in the suggested manner it is possible to form hollow box girdersmade up from a plurality of individual strips or trusses, whereinthercorners are circular or polygonal in cross-section. By providingsuitable openings in the bridging or corner filling strips, it ispossible to rivet the individual trusses together with little or nodiificulty after the bridging plates are in position. It is, moreover,possible to first secure the individual trusses into the compositegirder and to thereafter bridge the corners with suitable filler piecesof the type disclosed herein.

It will be appreciated that fillerstrips can be applied to hollow boxgirders of substantially any type or size whereby the same arematerially strengthened with very little increase in weight. The fillerstrip can itself take a number of difierent shapes and can be readilyadapted to bridge polygonal, semi-circular, triangular, or other shapedcorners, in accordance with the teachings of the present invention.

Again it is possible to secure the individual trusses together by meansother than rivets, as will be apparent, and similarly the bridging orfiller strips can be secured in position by other means.

While several embodiments of the invention have been described above andshown in the drawing, it will be appreciated that this is forpurposes ofillustration onlyand that the invention is limited only by the scope ofthe appended claims.

WhatIclaim is: .:v 1,

1. A hollow box girder comprising a plurality of trusses securedtogether along their edges to form a girder polygonal in cross-section,with certain of the trusses being shaped so thatthe corners of thegirder will form small, individual semi-polygonal columns, and bridgingmembers associated with the trusses and secured across each of thecorners of the girder and extending longitudinally thereof and closingthe semi-polygonal columns at the corners, said bridging members havingtheir extreme edges formed substantially perpendicular to the adjacentbody portion, said trusses and bridging members being: formed withopenings therethrough in order to.

ligten the same and to allow the trusses to. be secured together. I 2. Agirder comprising a plurality of trusses secured together along their.edges to 'form a girder polygonal incross-section, the trusses be? ingshaped so that the corners of the girder. will form small, individualsemi-polygonal columns, and bridging members associated with the trussesand secured across eachof the corners of the. girder and extendinglongitudinally thereof and closing the semi-polygonal columns at thecorners. 3. A girder made up of a plurality of individual. stripssecuredtogether at their longitudinaledges to form a hollow body, andbridging means ex-- tending across each of the corners of the hollow:

body to reenforce the securing points of the strips.

4. A beam for use in aircraft orthe like, comprising three or more thinmetal strips formed with weight reducing openings therein and havingedge portions adapted to be secured together in overlapping relation,said, edge portions forming partial columns at the corners of the beam,,

and corner members extending across the corners of the beam and closingthe columns, said bridg- '1 ing members having their extreme edgesformed substantially perpendicular tosthe adjacent body portion.

the girder and extending longitudinally thereof, and closing thesemi-polygonal columns .at the corners, said bridging membersterminating short of the ends of the girder;

. ,50 5. A girder comprising a plurality of trussessecured togetheralongtheir edges to form a girder 6. In combination, a plurality ofgirders, p ')lyg-- onal in cross-section, gusset plates connecting said.

girders together at their ends to form a joint, individual bridgingmembers placed across each corner of each girder and extending longitudinally thereof, said bridging membersterminating short of the joint atsubstantially of the gusset plates.

WOLFGANG B. KLEMPERER.

the beginning

